Leather surely can become hot - but you can also buy some very heavy denim stuff with protective barriers for your forearms, collar bones and back.
And the best and top of the list - a very good helmet, very good gloves, boots till ankles and knee slider. As a momento I have my busted helmet, scuffed boot and knee slider from an incident. I had crashed into the back chassis of a truck and survived to tell the story. Thats enough evidence for anyone to start using protective gear.
And the first and foremost safety is active safety - including NOT trying to stop the machine with your feet if its off balance. Seen it a million times in Pakistan.